Q29 / 160 · AP EAMCET 2024 (22 May Shift 2) · Chemistry

Which of the following reactions of $\mathrm{KMnO}_4$ occurs in acidic medium?

  • A
    Oxidation of thiosulphate to sulphate
  • Correct answer
    B
    Precipitation of sulphur from $\mathrm{H}_2 \mathrm{~S}$
  • C
    Oxidation of iodide to iodate
  • D
    Oxidation of manganous salt to $\mathrm{MnO}_2$

Solution

In acidic medium hydrogen sulphide is oxidsed, sulphur being precipitated $\begin{aligned} & \mathrm{H}_2 \mathrm{~S} \longrightarrow 2 \mathrm{H}^{+}+\mathrm{S}^{2-} \\ & 5 \mathrm{~S}^{2-}+2 \mathrm{MnO}_4^{-}+16 \mathrm{H}^{+} \longrightarrow 2 \mathrm{Mn}^{2+}+8 \mathrm{H}_2 \mathrm{O}+5 \mathrm{~S} \end{aligned}$

Hence, the correct answer is option: 'B'.

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